Flow rate control device, diagnostic device for use in flow rate measuring mechanism or for use in flow rate control device including the flow rate measuring mechanism and recording medium having diagnostic program recorded thereon for use in the same

A flow rate control device including a flow rate measuring mechanism configured to measure a flow rate of fluid flowing through a flow channel, a flow rate control valve provided on the flow channel, and a valve control part configured to control an opening degree of the flow rate control valve so as to reduce an error between a target flow rate value and a measurement flow rate value measured by the flow rate measuring mechanism, the flow rate control device comprising:

• a fluid resistor provided on the flow channel;
• a pressure sensor provided in any one of an upstream side or a downstream side of the fluid resistor;
• a stable state judging part configured to judge whether or not a state of the fluid flowing through the flow channel is in a stable state, based on the measurement flow rate value or a measurement pressure value measured by the pressure sensor;
• and
• an abnormality diagnosing part configured to diagnose an abnormality of the measurement flow rate value, based on a variation amount of the measurement pressure value, when the stable state judging part judges that the state of the fluid is in the stable state.